Tremec's New T-56 Transmission - A Better Mousetrap

Tremec Bumps Performance Up A Few Notches With Their New T-56 Magnum Six-Speed.

•Technology marches on, and just when we think it can't get any better, it's eventually surpassed by the something superior. This whole concept applies to automotive performance parts just like anything else. When the T-56 was introduced over a decade ago, it was a high-tech smooth-shifting wonder, and before long it was finding its way in early Camaros. But that was back when 500 hp was considered "up there." Since then, everyone, including the OEMs, started ramping up the output of their engines, and before long the original T-56 started to suffer under the strain of the added power, and more importantly, torque.

2/16

But Tremec, manufacturer of the T-56, had a solution-they called it the TR-6060. This new-generation six-speed would be able to easily handle whatever the OEMs could throw at it. While designed for cars like the new Camaro, GT500 Mustang, and Corvette, this new trans would pay huge dividends to hot rodders as well. The one problem Tremec ran into was that the OEM-specific design of the TR-6060 didn't lend itself to being "swap friendly." While the older T-56 used a direct shifter, the TR-6060 incorporated a remote system. It also lacked several features not needed on an OEM unit, but very much desired by the aftermarket. With that in mind, the engineers at Tremec came up with an aftermarket version called the T-56 Magnum. The Magnum combined the easy swapability of the older T-56 with the improved design of the new TR-6060. It was like chocolate and peanut butter-just the right combination for our older Camaros.

With the ability to withstand up to 700 lb-ft. of torque, it can handle all but the most insane powerplants. The direct-mount shifter can be reversed to accommodate various applications, and there's even a mid-shift provision. Triple-cone synchronizers on the first four gears, along with double-cone synchronizers on Fifth and Sixth (as well as reverse), result in smooth and accurate shifts, even at high rpm.

15/16

Tremec also fixed the main complaint we had about the older T-56, namely gearing. On the old model, you had to choose between having a good set of First through Third ratios, or a good set of Fifth and Sixth ratios. Generally, we went with the 2.66 First, 1.78 Second, 1.30 Third, and tolerated the 0.74 Fifth and 0.50 Sixth gear ratios. Don't get us wrong, a 0.50 Sixth gear is great for meeting C.A.F.E. gas mileage standards, but it's far from a performance ratio. And while the Vette gearing would yield a more zippy 0.80 Fifth and 0.62 Sixth gear, the obligatory 2.97 First gear proved incredibly short, especially with 3.90 rear gearing. We, along with others, bitched and Tremec listened. The result is a blending of the best of both gear sets.

The upshot to all of this is a 21st Century six-speed transmission that blends racing technology with smooth-shifting street manners. We wonder how they could possibly make it better, but then again, we've learned that there's always something new right around the corner. But for now, this will definitely fill the needs of virtually any hot rodder.

Sources

MORE PHOTOS

VIEW FULL GALLERY

xclose

Tremec's New T-56 Transmission - A Better Mousetrap

Also of note is that these new speed gears benefit from a significant advance in manufacturing techniques, namely two-piece laser beam-welded construction. Past units were one-piece forgings, which suffered from machining limitations. These new two-piece units allow for much greater control of tooth angles, pitch, and alignment while also featuring built-in positive stops to virtually eliminate the possibility of "overthrown" shifts.

Another critical aspect of the Magnum's improved strength over the previous T-56 is the radically bolstered one-piece countershaft (shown on right). Strength benefits are obvious and abundant. This larger shaft not only resists distortion far better than previous designs (shown on the left), but also prompted the use of larger bearings in all critical support areas for increased stability. You can also see the increased face widths on the T-56 Magnum gears.

The T-56 Magnum's input shaft (front) represents another significant strength upgrade in the transmission's first line of defense. Improvements include additional material throughout the length of the shaft, increased face width, a larger input bearing, and generously long splines to accommodate twin-disc clutch setups. As an additional strength consideration, all T-56 Magnums come equipped with 26-spline input shafts. 10-spline "Ford-style" units (rear) are no longer offered.

Allowing the space for the Magnum's wider gears is one of the cornerstones of its development-cutting-edge compact synchronizer technology. These all-new synchronizers are considerably narrower than their T-56 counterparts and feature fine-pitch tooth angles to effectively decrease the amount of travel necessary for engagement.

Not only are shift throws shortened, but thanks to new spring-loaded ball-type inserts, friction is greatly reduced. This translates into lower shift efforts and reduced "double-bump" during shifts, resulting in better shift feel. The new Magnum unit is on the left.

Another factor in the T-56 Magnum's greatly improved performance is the redesigned shift forks featuring integrated "shift keys" to virtually eliminate the possibility of bending shift forks. In such cases related to the original T-56, this action typically referred to as "bending" is in most cases actually a "wallowing" of the shift rail bore caused by aggressive or incorrect use in conjunction with the vulnerable keyway machined into the bore itself. Under high-stress conditions, the enlargement of the bore could cause deflection on the shift rail, sometimes resulting in serious engagement issues. The new design of the T-56 Magnum not only completely separates the links from the bores, but also casts them into the forks for greater precision and a more positive shift feel. Other points of interest regarding the shift forks are added cross-sectional material for increased rigidity and larger shift pads to promote better wear characteristics.

Here you can see the new Magnum next to a traditional T-56. The two main differences are the overall length (about 28.3 inches) and the shifter placement. While the case of the Magnum appears similar to the original T-56 in many respects, the main case and endplate of the Magnum have also undergone extensive modifications in order to safely handle extreme power loads from their intended applications. Throughout the transmission, material has been strategically placed to prevent leaks under high-stress conditions and increase overall power handling capabilities. This increased strength added a few pounds to the transmission, which comes in right around 130 pounds.

Here you can see the flexible shifter arrangement of the Magnum. The supplied rear shifter can be rotated easily and there's also a mid-shift provision under an inspection cover. Shifters for the older T-56 will not work with the new Magnum.

While the aftermarket hasn't caught up with the new Magnum in terms of shifters, Tremec does offer a mid-mount option.

The distance from the bellhousing flange back to the shifter is a hair over 21 inches. This is about 2 1/2 inches farther forward than a T-56 shifter. If you were to flip the shifter around, the distance to the front flange would be 17.5 inches. Nonetheless, it's fairly easy to use adapters (in the works from several companies), or various shift handles (already available) to position the shift knob in just the right spot.

Other changes from the T-56 revolve around the placement of various plugs. For example, this VSS sensor used to reside on the opposite side of a T-56 transmission.

In addition, the reverse lockout solenoid, while in the same spot, was rotated 180 degrees. The Magnum also offers the ability to run a mechanical speedometer that really increases the flexibility of the transmission in terms of installation into older cars.

Helping greatly to achieve the T-56 Magnum's remarkable 700 lb-ft of torque capacity rating are all-new speed gears similar to those found in the Tremec TR-6060. These gears feature substantially increased face widths, which are easily noted when compared to a like speed gear from an original T-56 (as shown on right).

We dug this transmission so much that we picked one up for our '68 track rat project

COMMENTS

related articles

Classic Motorsports Group and Tremec Transmissions provided a T-56 Magnum to be swapped in our 1968 Camaro, and we agree that the marketing hype actually pans out to be accurate. - Camaro Performers Magazine » Read More

Don't waste your time with a transmissions swap just because your 4L60E is driving you up the wall. Instead rebuild it with a Century overhaul kit and get a 600hp bullet-proof automatic transmission. Only at www.gmhightechperformance.com, the official site for GM High-Tech Performance Magazine. » Read More

If you're NOT looking to drop $2,800 on a new T56 Magnum trans, check out how you can get more life and better performance out of your Tremec T56 six-speed! Check out details and pictures at Camaro Performers Magazine. » Read More